CVE-2023-1430 in FluentCRM Marketing Automation Plugin
Summary
by MITRE • 06/09/2023
The FluentCRM - Marketing Automation For WordPress plugin for WordPress is vulnerable to unauthorized modification of data in versions up to, and including, 2.8.01 due to the use of an MD5 hash without a salt to control subscriptions. This makes it possible for unauthenticated attackers to unsubscribe users from lists and manage subscriptions, granted they gain access to any targeted subscribers email address.
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Analysis
by VulDB Data Team • 04/09/2026
The FluentCRM plugin for WordPress presents a significant security vulnerability classified as CVE-2023-1430, affecting versions up to and including 2.8.01. This weakness stems from the plugin's reliance on MD5 hashing without salt for subscription management controls, creating a critical pathway for unauthorized data manipulation. The vulnerability specifically targets the subscription management functionality, allowing attackers to modify user subscription status without proper authentication. The flaw operates on the principle that an attacker can exploit the predictable nature of unsalted MD5 hashes to generate valid control tokens for subscription modifications. This issue represents a direct violation of security best practices as outlined in CWE-327, which specifically addresses the use of weak cryptographic functions and the absence of proper salting mechanisms in security-sensitive contexts.
The technical exploitation of this vulnerability occurs when an attacker obtains access to a target subscriber's email address, which serves as the primary input for generating the MD5 hash used in subscription control. The lack of salt in the MD5 implementation means that the same email address will always produce the same hash value, making it susceptible to precomputation attacks and hash collision attempts. This vulnerability directly impacts the integrity and confidentiality of user subscription data, enabling attackers to perform unauthorized subscription management operations such as unsubscribing users from marketing lists or modifying their subscription preferences. The operational impact extends beyond simple data modification, as it can be leveraged to disrupt marketing campaigns, manipulate user engagement metrics, and potentially facilitate further attacks through compromised user data.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1213.002 which covers data manipulation through unauthorized access to user accounts and subscription systems. The attack vector requires minimal privileges and can be executed remotely without authentication, making it particularly dangerous for WordPress installations that rely heavily on subscription-based marketing automation. The vulnerability creates a persistent risk for organizations using FluentCRM, as compromised subscription controls can lead to unauthorized data modification, potential spamming of users, and disruption of marketing automation workflows. Security practitioners should note that this issue represents a classic example of insufficient randomness in cryptographic implementations, where the absence of proper salting creates predictable security tokens that can be exploited by attackers with minimal technical expertise.
The mitigation strategy for CVE-2023-1430 requires immediate attention from system administrators and security teams. Organizations should upgrade to the latest version of the FluentCRM plugin where this vulnerability has been addressed through proper cryptographic implementations that include salted hashing mechanisms. Additionally, security teams should implement network-level monitoring to detect suspicious subscription modification patterns and consider implementing rate limiting on subscription-related API endpoints. The vulnerability serves as a reminder of the critical importance of proper cryptographic implementation practices, particularly the necessity of using salted hashes for security-sensitive operations. Organizations should conduct comprehensive vulnerability assessments of their WordPress installations to identify similar weaknesses in other plugins or themes that may be using unsalted cryptographic functions for user management or access control purposes.